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Many photochemical or photobiological applications require the use of high power ultraviolet light sources, such as high-pressure mercury arc lamps. In addition, many photo-induced chemical, biochemical and biological applications require either a combinatorial setting or a parallel assay of multiple samples under the same environmental conditions to ensure reproducibility. To achieve this, alternative, controllable light sources, such as ultraviolet light emitting diodes (UV LEDs) with high power and spatial control are required. Preferably, LEDs are arranged in a suitable standardized 96-well microtiter plate format. We designed such an array and established the methods required for heat management and enabling stable, controllable illumination over time.
Zur Herstellung von langfristig stabilen Metall-Kautschuk-Verbunden sind chemische Haftvermittler notwendig. Nach Auftrag dieser wird Kautschuk mittels Gummispritzgießen auf die metallischen Grundkörper aufgebracht. In Klein- und Kleinstserien kann der Haftvermittler in präzisen Volumina händisch mit Hilfe eines Fluid-Dispensers aufgetragen werden. Allerdings verhindert dies eine Homogenität und Gleichheit der Schichtdicke, wodurch die Zuverlässigkeit und Stärke der Haftung variieren können. Als technische Lösung wurde ein Pipettierroboter avisiert. Mit Hilfe mehrerer mechanischer und elektrischer Adaptionen – so auch einer neuen Steuerungstechnik – wurden verschiedene Fluid-Dispenser auf 3-Achs-Portalfräsen integriert. Somit konnte die volle Funktionsfähigkeit erreicht werden.
Das Ziel dieses Projektes war es eine automatisierte Lösung für das Auftragen von Haftvermittlern auf metallische Grundkörper im Nanoliterbereich zu ermöglichen. Für die automatisierte Auftragung von Haftvermittler wurde eine neue Steuerungseinheit auf Grundlage eines Mainboards für die Ansteuerung von 3D-Druckern verwendet, als Firmware diente Marlin. Notwendig waren Anpassungen im Bereich der Motorströme, Geschwindigkeiten, Beschleunigung, Sensitivität, Druckbettgröße und Auswahl von Mainboard und Display. Für die Verfahrwege wurde G-Code mittels eines Programms in Python generiert. Für eine homogene und gleichmäßige Benetzung werden die einzelnen zu benetzenden Objekte angefahren und der Pipettiervorgang gesteuert. Es war möglich die vollständige Funktionsfähigkeit herzustellen.
A conductivity-based, batch-optimized system for analyzing the total of carbon parameter in water
(2023)
In cooperation with the company Purification Membranes Analytics GmbH (PMA), a prototype has been developed that analyzes the total organic carbon (TOC) content of water samples based on a complex conductivity measurement. In the process, a batchoptimized system was developed that delivers qualitative results even in highly polluted waters. This method requires small sample volumes and was assembled using an ultrapure water system, a sample mixing system, various electronic control units and a miniTOC system that uses a UV light source to decompose organic carbons and outputs differential values using two conductivity sensors. During the project, a fully automated prototype was developed and is ready for use. In the future, this method could support common methods and lead to more accurate statements on water quality in a cost-effective manner.
Synthetic substances like many pharmaceuticals, preservatives or other chemical compounds are actually very difficult to handle in sewage treatment. These compounds are very stable in aqueous solution and their degradation reactions are insufficient. Therefore, to eliminate these substances from wastewater additional afford is necessary. Extreme conditions like pH value, redox potential, chemical or physical energy need to be present. With our study we try to show that the use of plasma discharge could be a solution to this problem. Using the example of methylparaben, a preservative, we could show, that the physical energy of plasma discharge is able to initialize the degradation reaction in aqueous environment. The concentration was reduced by up to 70 percent in our setting depending on the treatment duration. Overall, the system showed potential to optimize wastewater treatment. Further examinations are necessary for example regarding undesirable by-products.
Processing biological materials with 3-dimensional (3D) printers has attracted increasing interest in several research areas. At the same time, off-the-shelf solutions are increasingly available in a wider variety to meet the current market demand. However, most of the available bioprinters are closed source, thus, modifications are quite challenging or require an avoidable consultation process with the manufacturer. Furthermore, the entry prices for basic machines amount to several thousands of euros. Whereas, high-end 3D bio printers with a vast array of features are available for several hundred thousand euros. Due to the immense potential of this tool in the field of biotechnology it is important to extend the availability of this technology for research purposes in terms of adaptability and price. This ongoing work focuses on open-source 3D printer heads with the ability to extrude biological materials. The print heads include several techniques to process low as well as high viscose biomaterials such as agar and gelatin. Additionally, obstacles such as continuous substrate tempering or integration into existing 3D printers are addressed. The work presented is open source and thus freely adaptable to any user’s specific needs. Our goal is to process a diverse range of biomaterials with different print techniques.
New technologies leading to better and more efficient light emitting diodes. The emitted radiation reaches higher energy levels and lower wavelengths especially in the UV-C spectrum. UV-C light has a cancer inducing effect on human cells. Therefore it is necessary to work in a safe way with those devices.
This work is focused on an open-source solution for rapid 3D printing of an safe UV-C radiation measuring device. Especially for research groups or universities which can not afford big safety labs.
After modeling and printing the prototype, a series of tests has shown the functionality of that UV-C Diode test system. By using black printing filaments and infill rates over 50 %, the transmission of light could be prevented and the system worked well.
A passive pipe sampler device for contaminant analysis in groundwater was developed which create a permanent sampling flow from groundwater and in addition to temperature, conductivity and pressure, now also has room for specific sorbents. The large surface of the adsorber offers more binding surface for the analyte and the constant movement of the sorbent with fresh groundwater also provides homogeneous binding. The spectroscopic analyses at the monitoring site of the pipe passive sampler for groundwater monitoring points enables a measurement-based validation of the sorbent circulation as an alternative to a visual assessment. The optimum pump speed for the sorbens Lewatit® M500 and SR7 was evaluated. The 42mm slim measuring device allows the use in DN50 monitoring well and thus allows the setup of a closer measuring network.